1. Field of the Invention
The present invention relates to a medical device for placement at a predetermined location within a passageway of the human body, and more particularly, relates to a flexible embolization device which may be delivered by a catheter to a pre-selected position within a blood vessel to thereby embolize a blood vessel or a defect in a blood vessel, such as an aneurysm or fistula.
2. Description of the Prior Art
For many years flexible catheters have been used to place various devices within the vessels of the human body. Such devices include dilatation balloons, radiopaque fluids, liquid medications and various types of occlusion devices such as balloons and embolic coils. Examples of such catheter devices are disclosed in U.S. Pat. No. 5,108,407 to Geremia, et al., entitled, xe2x80x9cMethod And Apparatus For Placement Of An Embolic Coilxe2x80x9d and U.S. Pat. No. 5,122,136to Guglielmi, et al., entitled, xe2x80x9cEndovascular Electrolytically Detachable Guidewire Tip For The Electroformation Of Thrombus In Arteries, Veins, Aneurysms, Vascular Malformations And Arteriovenous Fistulas.xe2x80x9d These patents disclose devices for delivering embolic coils at predetermined positions within vessels of the human body in order to treat aneurysms, or alternatively, to occlude the blood vessel at a particular location.
Coils, which are placed in vessels, may take the form of helically wound coils, or alternatively, may be random wound coils, coils wound within other coils or other such coil configurations. Examples of various coil configurations are disclosed in U.S. Pat. No. 5,334,210 to Gianturco, entitled, xe2x80x9cVascular Occlusion Assemblyxe2x80x9d and U.S. Pat. No. 5,382,259 to Phelps, et al., entitled, xe2x80x9cVasoocclusion Coil With Attached Tubular Woven Or Braided Fibrous Coverings.xe2x80x9d Embolic coils are generally formed of radiopaque material, such as platinum, gold, tungsten or alloys of these metals. Often times several coils are placed at a given location in order to occlude the flow of blood through the vessel by promoting thrombus formation at the particular location.
In the past, embolic coils have been placed within the distal end of a catheter and when the distal end of the catheter is properly positioned the coil may then be pushed out of the end of the catheter with, for example a guidewire, to release the coil at the desired location. This procedure for placement of the embolic coil is conducted under fluoroscopic visualization such that the movement of the coil through the vasculature of the body may be monitored and the coil may be placed in the desired location.
Other embolization devices, such as detachable balloons, are placed in vessels or aneurysms. These balloons usually take the form of an inflatable elastic balloon with a valve assembly for sealing the balloon when a desired inflation is reached. Examples of various detachable balloons are disclosed in U.S. Pat. No. 4,517,979 to Pecenka, entitled, xe2x80x9cDetachable Balloon Catheterxe2x80x9d and U.S. Pat. No. 4,545,367 to Tucci, entitled, xe2x80x9cDetachable Balloon Catheter And Method Of Use.xe2x80x9d Detachable balloons are generally formed of a flexible polymer and are inflated with a radiopaque solution for visualization under fluoroscopy. Often several balloons are used to fill the aneurysm space. These balloons do not generally conform to the aneurysm space thereby leaving unoccupied space leading to an incomplete aneurysm embolization. Often times a balloon valve may leak thereby causing other balloons to shift position, which may in turn, occlude the parent artery leading to severe complications.
In accordance with one aspect of the present invention, the vascular embolization system comprises a catheter, a push rod and an embolization device. The embolization device takes the form of an embolization coil surrounded by a foam sleeve. The foam sleeve has a hydrated normal expanded diameter, however it may be compressed and remain compressed when constrained. When the foam sleeve is hydrated and unconstrained, the foam sleeve will return to its normal expanded diameter. The embolization device is positioned in the lumen of the catheter. The push rod is slidably received by the lumen of the catheter and engages the embolization device. Distal movement of the push rod causes the embolization device to exit the lumen of the catheter at a predetermined site within a blood vessel.
In accordance with another aspect of the present invention, there is provided an embolization system comprising an embolization device, which takes the form of an embolization coil, which is impregnated and surrounded by a foam sleeve made of a moldable material. Preferably, the foam sleeve extends into the lumen of the coil.
In another aspect of the present invention there is provided an embolization system, which includes an embolization device having an embolization coil and a foam sleeve bonded to the coil. The embolization device takes the form of a helix. The embolization device is positioned in the lumen of a catheter in a generally straightened configuration, however, upon exiting the distal lumen of the catheter the embolization device returns to the relaxed helical shape. Alternately, the embolization device may take the form of a convoluted shape.
In accordance with another aspect of the present invention there is provided an embolization device that comprises an embolization coil with a foam sleeve disposed about the periphery of the coil. The foam may take the form of a hydrogel and in addition, the embrolization device may be used to deliver a therapeutic agent to improve the efficacy of a particular treatment modality. The choice of therapeutic agent depends largely on the particular treatment chosen for a vascular abnormality. In the treatment of an aneurysm the therapeutic agent may be a growth factor such as fibroblast growth factor (FGF) or vascular endothelial growth factor (VEGF) to promote endothelialization and permanent occlusion of the aneurysm. Other therapeutic agents include radioactive materials to aid in the treatment of arteriovenous malformations. Other therapeutic agents include drugs used to obliterate tumors.
In accordance with yet another aspect of the present invention, there is provided an embolization device having an embolization coil and foam sleeve disposed about the coil periphery, which is radiopaque. The embolization device may be made visible under fluoroscopy by using an embolization coil made from a radiopaque material such as a platinum or tungsten alloy. Alternatively, the foam sleeve may be made radiopaque by incorporating a radiopaque filler material such tantalum or tungsten powder or a radiopaque iodine commonly used in contrast media such as RENOGRAFFIN. This radiopaque material aids in the visualization of the embolization device during the medical procedure.
In still another aspect of the present invention there is provided an embolization device that comprises an embolization coil and a foam sleeve bonded to the coil. The embolization coil may contain reinforcing fiber or fibers that are secured in at least two locations and extend through the lumen of the coil to reduce coil stretching. Alternatively, the foam sleeve may contain reinforcing material dispersed throughout the foam, such as long fibers to resist stretching or short fibers or particles to improve sponge mechanical integrity.
In accordance with another aspect of the present invention there is provided an embolization device that comprises an embolization coil surrounded by a foam sleeve. The foam sleeve has a hydrated normal expanded diameter, however, it can be compressed and remain compressed when constrained. When the foam sleeve is hydrated and unconstrained the foam sleeve will return to its normal expanded diameter. Typically, the normal expanded diameter of the foam sleeve is larger than the diameter of the lumen of the catheter.
In accordance with yet another aspect of the present invention there is provided an embolization device that comprises an embolization coil surrounded by a foam sleeve. The foam sleeve has a hydrated normal expanded diameter, however, it can be compressed and remain compressed when constrained. When the foam sleeve is hydrated and unconstrained the foam sleeve will return to its normal expanded diameter. Typically, the normal expanded diameter of the foam sleeve is smaller than the diameter of the catheter used to deliver the embolization device.
In accordance with another aspect of the present invention there is provided a vascular embolization system comprising a push rod, a catheter and an embolization device. The embolization device takes the form of an elongated flexible cylindrical resilient foam. The foam has a normal hydrated expanded diameter and a smaller constrained diameter. When the foam is unconstrained and hydrated the foam returns to the normal expanded diameter. This elongated flexible foam has a length that is at least ten times greater than the normal hydrated diameter.
In another aspect of the present invention there is provided an embolization device, which takes the form of an elongated flexible foam. The foam may take the form of a hydrogel. The foam may be used to deliver therapeutic agents to improve the efficacy of a particular treatment modality.
In yet another aspect of the present invention there is provided an embolization device, which takes the form of an elongated flexible cylindrical foam. To improve the mechanical integrity of the foam, the foam may contain reinforcing materials. Reinforcing materials may take the form of long fiber or fibers incorporated within the foam or short fibers or particles dispersed throughout the foam.
In still another aspect of the present invention there is provided an embolization device, which takes the form of an elongated flexible foam. The foam may be made visible under fluoroscopy by incorporating a radiopaque filler material such tantalum or tungsten powder or a radiopaque iodine commonly used in contrast media such as RENOGRAFFIN. This radiopaque material aids in the visualization of the embolization device during the medical procedure.
In accordance with yet another aspect of the present invention there is provided an embolization system comprising a push rod, a catheter and an embolization device. The embolization device takes the form of an elongated resilient flexible foam having an elongated length that is at least ten times the normal hydrated diameter. The foam takes the shape of a helix. The embolization device is positioned in the lumen of the catheter in a generally straightened configuration. The push rod is slidably disposed into the catheter lumen engaging the embolization device. Distal movement of the push rod causes the embolization device to exit the lumen of the catheter. As the embolization device exits the distal section of the catheter lumen and enters the blood vessel the embolization device returns to its relaxed helical shape. Alternately, in treating a blood vessel defect such as an aneurysm, the embolization may have a preferred convoluted shape.
In accordance with another aspect of the present invention there is provided an embolization system comprising a push rod, a catheter and an embolization device. The embolization device takes the form of an elongated flexible resilient cylindrical foam. The foam has a normal expanded diameter when hydrated and a smaller compressed diameter when constrained. The normal expanded diameter of the foam may be larger than the diameter of the lumen of the catheter.
In accordance with another aspect of the present invention there is provided an embolization system comprising a push rod, a catheter and an embolization device. The embolization device takes the form of an elongated flexible resilient cylindrical foam. The foam has a normal expanded diameter when hydrated and a smaller compressed diameter when constrained. The normal expanded diameter of the foam material may be smaller than the diameter of the catheter used to deliver the embolization device.
In accordance with yet another aspect of the present invention there is provided a vascular embolization system comprising a push rod, a catheter and an embolization device. The embolization device includes a flexible wire and a resilient foam sleeve disposed about the wire. The foam sleeve has a normal hydrated expanded diameter and a smaller constrained diameter such that when unconstrained and hydrated said foam sleeve returns to the normal expanded diameter.